Successful poker players often need to blend both psychological and mathematical skills to excel at the game. Both. You need to understand pot odds and implied odds, which is somewhat mathematical & though it is not difficult to come up with a decent approximation.
Poker is a game of math. The math can range from simple things like figuring out the size of the pot to very complex things like calculating the EV of multi-street plays. But poker is also a social/psychological game where tells, psychology, and dynamics come into play (especially in live & casino poker).